Insulated duct with air gap and method of use

ABSTRACT

A flexible air duct contains a uniformly-spaced reflective insulation system, with or without bulk insulation, a liner, and an outer jacket that would allow a reduced amount or no amount of bulk insulation to be used to obtain a desired R-value insulation. The flexible air duct can be used to move conditioned air to one or more desired locations.

This application is a Divisional of U.S. Ser. No. 15/359,898 filed onNov. 23, 2016, which claims priority under 35 USC 119(e) based onprovisional application No. 62/258,607, filed on Nov. 23, 2015.

FIELD OF THE INVENTION

The invention relates to a flexible air duct that contains auniformly-spaced reflective insulation system, with or without bulkinsulation, a liner, and an outer jacket that would allow a reducedamount or no amount of bulk insulation to be used.

BACKGROUND ART

The construction of factory-made flexible HVAC ducts is well known inthe industry. These types of ducts usually comprise a helical-supportedduct liner (sometimes referred to as the liner or inner liner) coveredby a layer of fiberglass insulation, which is, in turn, covered by ascrim-reinforced PET vapor barrier or a PE-film vapor barrier. Scrim isa woven material that adds strength to a laminate construction when madea part thereof. U.S. Pat. Nos. 6,158,477 and 5,785,091 show typicalconstructions of factory made ducts. U.S. Pat. No. 5,785,091 teachesthat the duct liner and vapor barrier can be manufactured from polymerfilms, particularly polyester. U.S. Pat. No. 5,526,849 discloses aplastic helical member in combination with a metal helical member andU.S. Pat. No. 4,990,143 discloses a polyester helix. United StatesPatent Publication No. 2007/0131299 discloses a polyester scrim used ina vapor barrier (outer jacket).

In the prior art, factory-made flexible HVAC ducts are typicallyconstructed of three main components; a duct liner for conveying air, alayer of insulation for preventing energy loss through the duct wall,and a vapor barrier for holding the fiberglass around the liner whileprotecting the fiberglass from moisture. The duct finer is commonlyconstructed of a steel wire sandwiched between layers of polyester (PET)film. Other plastics and coated fabrics are also used to construct thewall of the duct liner. United States Published Patent Application No.2010/0186846 to Carlay et al. is another example of flexible duct and itis incorporated in its entirety herein.

Another example of a prior art duct is that shown in United StatesPublished Patent Application No. 2015-0090360 to Carlay II. This ducthas an inflatable jacket to create an air space around the duct core orliner to reduce the amount of bulk insulation in the duct withoutreducing the overall insulating value of the duct. While this duct isadvantageous in terms of its insulating value, it has some drawbacks interms of manufacture to create the inflatable jacket.

In the HVAC industry, ductwork is often times specified to have acertain thermal resistance or R value for a particular application. Forexample, if the ductwork is to run in an unconditioned space, the Rvalue must be at least 6.0. Current North American flexible ductfiberglass R-values are R4.2, R6.0 and R8.0 and each may be purchasedpre-certified from fiberglass manufacturers. Obviously, the cost of theductwork increases from one that has an R6.0 value to an R8.0 value dueto the need to provide additional insulation, which is generallyfiberglass insulation.

In the HVAC industry, the fundamentals of heat transfer and the like areexplained in the ASHRAE Handbook of Fundamentals (the Handbook), whichis currently in a 2013 edition. Included in this Handbook is therecognition of reflective insulation systems, which combines areflective insulation and an enclosed air space bounded within aparticular assembly, see page 26.12 of the Handbook. The Handbook alsorecognize the effect of thermal resistance as it relates to a particularsize air space and the direction of heat flow, e.g. up, down, oblique upor down, etc., see pages 26.13 and 26.14. What these pages generallyshow is that an increase in thermal resistance occurs when the air spaceor air gap increases and that the thermal resistance is the least whenthe heat flow is in the up direction.

It is known to provide an HVAC duct that uses a free floating liner tocreate However, there is always a need to provide improved duct designsin the HVAC industry and other areas where air or fluid handling isnecessary. The present invention responds to this need by providing animproved insulated duct.

SUMMARY OF THE INVENTION

One object of the invention is to provide a flexible insulated duct thatprovides improved performance over existing ducts, which are typicallyused in HVAC applications.

Another object of the invention is to provide a method of movingconditioned air using the inventive flexible insulated duct.

One feature of the inventive duct is a spacer system that creates auniform airgap as part of reflective insulation system of the duct.

The inventive insulated flexible duct comprises a liner, a reflectiveinsulation system surrounding the liner, and at least one jacketsurrounding the reflective insulation system. The reflective insulationsystem further comprises at least one low emissivity reflective surfaceand at least one spacer system positioned between the liner and thejacket, the spacer system creating a generally uniform air gap betweenan outer surface of the liner and the inner surface of the jacket tocreate additional R value for the flexible insulated duct.

The spacer system may include a number of different designs to createthe generally uniform air gap. One such design is a star-shaped spiralhelix positioned between the outer surface of the liner and the innersurface of the at least one jacket to create the generally uniform airgap between the outer surface of the liner and the inner surface of theat least one jacket. The star-shaped spiral helix can be attached orunattached to the liner and/or to the at least one jacket.

Another design of the spacer system is an expandable lattice blanketpositioned between the outer surface of the liner and the inner surfaceof the at least one jacket to create the generally uniform air gapbetween the outer surface of the liner and the inner surface of the atleast one jacket.

Yet another design for the spacer system is a plurality of spaced-apartstaves, each spaced-apart stave extending from the outer surface of theliner to create the generally uniform air gap between the outer surfaceof the liner and the inner surface of the at least one jacket.

One further design for the spacer system is a lattice cord and postblanket assembly surrounding the outer surface of the liner. Tensioningof the lattice cord of the lattice cord and post blanket assemblycausing posts thereof to orient in a generally perpendicular directionwith respect to the outer surface of the liner to create the generallyuniform air gap between the outer surface of the liner and the innersurface of the at least one jacket.

The flexible insulated duct can include at least one bulk insulatinglayer. This layer can be positioned between an outer periphery of the atleast one spacer system and the inner surface of the jacket such thatthe generally uniform air gap is created between the outer surface ofthe liner and an inner surface of the at least one bulk insulatinglayer. Alternatively, the at least one bulk insulating layer can bepositioned between an outer periphery of the liner and an innerperiphery of at least one spacer system such that the generally uniformair gap is created between an outer surface of the at least one bulkinsulating layer and an inner surface of the at least one jacket.

In another embodiment, a plurality of the at least one spacer system andthe at least one jacket can be arranged to create a plurality ofgenerally uniform air gaps.

For the spacer system using the expandable lattice blanket, it can bemade of a sheet of foam with openings therein wherein expansion of thesheet of foam creates lattice openings or strips of foam connectedtogether at spaced apart locations to create the lattice openings.

For the spacer system using the staves, each of the spaced apart stavesare attached at one end thereof to the outer surface of liner such thatwhen the liner is expanded, free ends of the spaced apart staves extendaway from the outer surface of the liner to create the generally uniformair gap and when the liner is compressed, ends of the spaced apart movetoward the outer surface of the liner.

The liner can comprise a pair of polymer films, one polymer film formingan inner surface of the liner and the other polymer film forming theoutside surface of the liner. Optionally, a helical member can bedisposed between the polymer films.

The jacket can comprise either two layers of polyester film that areadhered together, the two layers encapsulating a scrim blankettherebetween or a continuous tube of polyethylene material.

The at least one low emissivity surface is on either an inner surface ofthe at least one jacket or the outer surface of the liner.

The invention also includes a method of supplying conditioned air to aspace using the inventive flexible insulated duct.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of one embodiment of the invention showinga star-shaped helical member to create the generally uniform air gap forthe duct.

FIG. 2 is an end view of the arrangement of FIG. 1 surrounded by bulkinsulation and an outer jacket.

FIG. 3 is a perspective view of a second embodiment of the inventionshowing the liner of FIG. 1 with a lattice construction to create thegenerally uniform air gap.

FIG. 4 is a side perspective view of the duct of FIG. 3.

FIG. 5 is a perspective view of a third embodiment of the inventionshowing the liner of FIG. 1 and a plurality of staves to create thegenerally uniform air gap of the duct.

FIG. 6 is a side perspective view of the duct of FIG. 5 in a morecompressed or collapsed state to show the change in the orientation ofthe staves.

FIG. 7 is an end view of the duct of FIG. 5 surrounded by bulkinsulation and an outer jacket surrounding the bulk insulation.

FIG. 8 is perspective view of a fourth embodiment of the inventive ductshowing the liner of FIG. 1 with a lattice post and cord construction tocreate the uniform air gap.

FIG. 9a is a schematic view of the lattice post and cord construction ofFIG. 9 in a collapsed state.

FIG. 9b is a schematic view of the lattice post and cord construction ofFIG. 9 is a tensioned state.

FIG. 9c is a top view of the schematic of the lattice post and cordconstruction of FIG. 9a showing the one of the lattice network cords andposts.

FIG. 10 is an end view of the duct of FIG. 8 surrounded by bulkinsulation and an outer jacket.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a number of different ways to create auniform spaced reflective insulation system as part of an HVAC duct thatcomprises a liner, the reflective insulation system surrounding theliner, and at least one jacket surrounding the reflective insulationsystem. The reflective insulation system further comprises at least onelow emissivity reflective surface. The at least one spacer system ispositioned between the liner and the jacket. The spacer system creates agenerally uniform air gap between an outer surface of the liner and theinner surface of the jacket to create additional R value for theflexible insulated duct. The R-value of the duct can be enhanced byusing one or more bulk insulation layers as part of the duct.

One of the spacer systems has a star helix construction. With referenceto FIGS. 1 and 2, this design is designated by the reference numeral 10and comprises an inner liner 1 shown in FIG. 1 with a low emissivityreflective outer surface 3 (hereinafter low-e surface). An example of aliner construction is a pair of polymer films, one polymer film formingan inner surface of the liner and the other polymer film forming theoutside surface of the liner and, optionally a helical member disposedbetween the polymer films. In the FIG. 1 embodiment, a helical member 4is shown as part of the liner 1. Any type of conventional liner can beused as part of the duct.

A formed star-shaped spiral wire helix 5 is wrapped around the liner 1and is locked in place with a set pitch between wire flights. The starformation creates uniform spiral support sections as shown in FIG. 1.

A blanket of fiberglass bulk insulation 7 can be then wrapped around theliner and star helix as shown in FIG. 2. An outer jacket 9 is thenpulled over the construction to hold the insulation in place. An exampleof a jacket is either two layers of polyester film that are adheredtogether, the two layers encapsulating a scrim blanket therebetween or acontinuous tube of polyethylene material. As with the liner, any type ofouter jacket known for use in flexible insulated ducts can be employedas part of the duct.

The generally uniform air gap compartment created by the spiraling starhelix is indicated by reference numeral 11.

Although not illustrated, the star helix design may also be utilizedbetween the fiberglass bulk insulation 7 and the outer jacket 9, withthe inner surface of the jacket having the low-e surface. The air gap inthis embodiment created by the star-shaped spiral wire helix 5 residesbetween the outer surface of the bulk insulation 7 and the inner surfaceof the jacket 9.

The creation of a uniformly-spaced air gap as part of the insulated ductprovides a number of benefits. The spaced reflective insulation systemcreates additional R value that is independent of the fiberglass bulkinsulation. This design can also be utilized with or without thefiberglass bulk insulation.

This design can be used to create multiple layers of radiant air gapswith flexible air ducts by employing more than one star-shaped spiralhelix and creating more than one air gap.

The construction allows for the air duct to be compressed and packagedin a reduced size to the customer without being damaged. The star-shapedspiral helix provides added crush resistant support to the air ductconstruction. The presence of the air gap allows the compressed air ductto recovery more quickly once removed from the compressed state in thepackage.

This embodiment provides a lighter weight design compared to the same Rvalue with standard fiberglass bulk insulation. The star-shaped spiralhelix may be recycled at the end use of product and can be made of anymaterial, metallic or non-metallic.

With reference to FIGS. 3 and 4, a second reflective insulation systemthat can be used instead of the star-shaped spiral helix is designatedas 20 and comprises a lattice construction. This design employs the sameinner liner 1 shown in FIG. 1 with its low-e reflective outer surface 3.An expandable lattice blanket 21 is wrapped around the liner forming aplurality of air pocket compartments 23 as it is stretched and pulledtight in all directions as shown in FIGS. 3 and 4.

The lattice blanket formation creates a uniform compartmentalized airgap around the liner as a result of the formation of the plurality ofpockets 23. The lattice blanket can be made with different foam and/orplastic materials. The lattice blanket can be constructed severaldifferent ways: cutting slits into a sheet of foam allowing it to expandonce pulled, connecting strips of plastic or foam in various spots sothat when pulled the blanket stands upright as shown in FIGS. 3 and 4.

Still referring to FIGS. 3 and 4, the lattice design has a number ofsegments 25 that merge at one connection point 27, then diverge from theone connection point 27 to merge with another segment 26 at anotherconnection point 28 so as to create the lattice design. The connectionpoints 27 and 28 can be formed using any connection technique, e.g., afastener like a staple 29, an adhesive, or the like.

Although not shown, a blanket of fiberglass bulk insulation can then bewrapped around the liner 1 and lattice blanket 21. An outer jacket isthen pulled over the construction to hold the insulation in place. Theuse of the bulk insulation and outer jacket is the same as for the FIG.1 embodiment so that the insulation and outer jacket for the latticeembodiment do not require illustration.

The lattice design may also be utilized between the fiberglass bulkinsulation and the outer jacket, with the inner surface of the jackethaving the low-e surface.

The lattice design has a number of benefits including that the spacedreflective insulation system created by the lattice design creates anadditional R value that is independent of the fiberglass bulkinsulation. This design can be utilized with or without the fiberglassbulk insulation. This design can be used to create multiple layers ofradiant air gaps for flexible air ducts The construction allows for theair duct to be compressed and packaged in a reduced package to thecustomer without being damaged. The presence of the air gap allows theair duct in the compressed state to recovery quicker once removed fromthe compressed state in the package. The design also provides a lighterweight design compared to the same R value with standard fiberglass bulkinsulation. The material used to create the space can be recycled at theend use of product.

Another spacer design involves the use of staves and is designated bythe reference numeral 30. With reference to FIGS. 5-7, this designconsists of an inner liner 1 like the one shown in FIG. 1 with the low-eouter surface 3 and helical member 4. Integrated into the inner liner 3are a plurality of stave spacers 31. The stave spacers 31 are evenlydistributed around the outside surface of the liner 1 and along a lengththereof as shown in FIG. 5.

The staves can be attached to the liner in any way. They can beindividually attached using an adhesive or the like or attached to afilm blanket in a spaced apart manner with the film blanket wrappedsecurely around the liner so that the stave spacers 31 are distributedalong the length and circumference of the liner 1.

When the liner is compressed or collapsed, the staves are designed sothat they lay down flat against the compressed liner as shown in FIG. 5.When the duct is expanded to its working length, the staves 31 stand upas shown in FIG. 5, thereby creating the generally uniform air gap 11 ofFIG. 7. In this configuration, each end of the staves has a flange 32that would contact either the outer jacket or bulk insulation. Ofcourse, other shapes could be used at the free end of the staves tofacilitate supporting the surrounding structure, whether it be just anouter jacket or bulk insulation.

The staves can be manufactured using plastic or metal material. Ablanket of fiberglass bulk insulation 7 is then wrapped around the linerand stave assembly which is shown in FIG. 7. An outer jacket 9 is thenpulled over the construction to hold the insulation in place as shown inFIG. 7.

The stave design has the same benefits as the other spacer systemdesigns discussed above.

Yet a further design of the spacer system is designated by the referencenumeral 40 and is shown in FIGS. 8-10. This design is a lattice cord andpost blanket assembly.

This design consists of an inner liner 1 like that shown in FIG. 1 withits low-e outer surface 3 and helical member 4. A lattice cord and postblanket assembly 41 is wrapped around the inner liner 1. Referring toFIGS. 9a and 9b , the assembly 41 comprises has a number of posts 43 anda pair of lattice cords 45 and 46. The posts 43 are connected betweenthe lattice cords 45 and 46 at connection points 47. The connection canbe made in any way, with one way using an adhesive placed on the end ofthe post 43 to hold the lattice cord in place.

When the lattice cord and post blanket assembly is pulled from one orboth ends of the duct that it surrounds, a continuous air gap is formedas the lattice cord is stretched and pulled tight as shown in FIGS. 8 to10. The lattice cord and post blanket assembly creates a uniform air gap49 around the liner. The lattice cord and post blanket made up of aseries of linked lattice cords can be made of plastic or metal material,that intertwines with the posts that may also be made up of eitherplastic or metal materials. When the lattice is pulled tight the cordapplies tension to the posts which causes them to stand perpendicular tothe outer surface of the liner creating the air gap 49 shown in FIG. 9b. FIG. 9a shows the lattice cord assembly in a collapsed state when theassembly is not tensioned. FIG. 9c shows a top view of one of thelattice cords 45 and posts 43 in a vertical orientation.

A blanket of fiberglass bulk insulation 7 is then wrapped around theliner and lattice blanket which is shown in FIG. 10. An outer jacket 9is then pulled over the construction to hold the insulation in place.

The lattice cord and post blanket assembly may also be utilized betweenthe fiberglass bulk insulation and the outer jacket, with the innersurface of the jacket having a low emissivity reflective surface.

The same benefits as outlined above for the other spacer designs arerealized with the lattice cord and post embodiment.

The inventive flexible insulated duct can be used in any applicationthat requires movement of conditioned air and as a substitute forconventional HVAC ducting.

Again, the collapsible nature of the spacer system offers significantadvantages in terms of shipping and packaging. The inventive ductcreates a significantly reduced package length while containing the sameduct length. This is accomplished by the following:

1) the presence of a generally uniform air gap between the inner linerand a fiberglass bulk insulation, when used, better allows theevacuation of air from the insulation during the compression of theproduct;

2) the flexible nature of the spacer system also allows space for theinner liner to freely move during the compression process (this gapallows for both the layer of insulation and the inner liner to betterfold and flatten inside the duct construction); and

3) the presence of the spacer system that holds the insulation againstthe outer jacket or holds the outer jacket also provides increased crushresistance during the packaging process.

Currently, the current flexible duct industry compresses and packagesproduct in both corrugated boxes and polyethylene bags. Standard ductscome in twenty-five foot lengths ranging from four to twenty-two inchinner diameter product. The industry standard pack height for R4.2 andR6 box and bag product is approximately 20″-25″. The industry standardpack height for R8 box and bag product is approximately 25″-30″. Thecollapsible nature of the inventive duct allows for the duct to becompressed and packed in a box or bag of considerably less height(length). In contrast, the current standard flexible duct would havepermanent deformation to the liner at a reduced pack height. It has beendetermined that current industry standard flexible duct can only becompressed and packaged no less than 20″-25″ pack height before linerdamage occurs. Damage to liner will cause reduced air flow and/orleakage.

Having a reduced pack height allows for increased skid capacity for boxand bag product. This increased capacity allows for more inventive ductto be loaded and shipped on containers to the customer. Typically,flexible duct freight cost is approximately 8% of the total product costof sales, so the reduced package height offers a significant savings tothe flexible duct manufacturer.

A reduced pack height also allows for the customer to utilize lesswarehouse space to store the product before being used. Flexible duct istypically the lowest value item for HVAC equipment that is stored in adistributor's warehouse. Given the fact that this product is can occupyless space in the warehouse the distributor has more space for highervalue product to stock.

The reduced compression and overall duct package length also means thatthere is less package material being used for the total package. Thisensures that less corrugated box and polyethylene bag is used perpackaged duct, thereby resulting in less packaging material cost for theproduct. The advantages in terms of less packaging material, less weightfor transportation, and less warehouse space also result in a smallerenvironmental footprint.

The presence of the generally uniform gap also allows the duct torecover faster than conventional ducts. As noted above, the duct is in acompressed form when made and delivered to an installation site. Oncethe packaging is open, the duct has to recover or expand sufficientlybefore it is ready for installation. The air gap of the inventive ductallows air to more easily infiltrate the duct and accelerate therecovery or expansion of the duct. This leads to improved productivityduring duct installation as the installer does not have to wait as longfor the duct to recover.

For Class 1 flexible ducts, the duct material would be tested to andcomply with UL 181 standards, which includes flame resistance at aminimum to pass the Flame Penetration test method in UL 181.

As such, an invention has been disclosed in terms of preferredembodiments thereof which fulfills each and every one of the objects ofthe present invention as set forth above and provides a new and improvedinsulated flexible duct and method of use.

Of course, various changes, modifications and alterations from theteachings of the present invention may be contemplated by those skilledin the art without departing from the intended spirit and scope thereof.It is intended that the present invention only be limited by the termsof the appended claims.

We claim:
 1. An insulated flexible duct comprising: a liner; areflective insulation system surrounding the liner, and at least onejacket surrounding the reflective insulation system, the reflectiveinsulation system further comprising: at least one low emissivityreflective surface; and at least one spacer system positioned betweenthe liner and the jacket, the spacer system creating a generally uniformair gap between an outer surface of the liner and the inner surface ofthe jacket to create additional R value for the flexible insulated duct,wherein the spacer system further comprises a star-shaped spiral helixpositioned between the outer surface of the liner and the inner surfaceof the at least one jacket to create the generally uniform air gapbetween the outer surface of the liner and the inner surface of the atleast one jacket.
 2. The flexible insulated duct of claim 1, wherein atleast one bulk insulating layer is positioned between: an outerperiphery of the at least one spacer system and the inner surface of thejacket such that the generally uniform air gap is created between theouter surface of the liner and an inner surface of the at least one bulkinsulating layer; or an outer periphery of the liner and an innerperiphery of at least one spacer system such that the generally uniformair gap is created between an outer surface of the at least one bulkinsulating layer and an inner surface of the at least one jacket.
 3. Theflexible insulated duct of claim 2, further comprising a plurality ofthe at least one spacer system and the at least one bulk insulatinglayers arranged to create a plurality of generally uniform air gaps. 4.The flexible insulated duct of claim 1, further comprising a pluralityof the at least one spacer system and the at least one jacket arrangedto create a plurality of generally uniform air gaps.
 5. The flexibleinsulated duct of claim 1, wherein the at least one spacer system isunattached to the liner or the at least one jacket.
 6. The flexibleinsulated duct of claim 1, wherein the jacket further comprises eithertwo layers of polyester film that are adhered together, the two layersencapsulating a scrim blanket therebetween or a continuous tube ofpolyethylene material.
 7. The flexible insulated duct of claim 1,wherein the at least one low emissivity surface is on either an innersurface of the at least one jacket or the outer surface of the liner. 8.In a method of supplying conditioned air to a space using a flexibleinsulated duct, the improvement comprising using the duct of claim
 1. 9.An insulated flexible duct comprising: a liner; a reflective insulationsystem surrounding the liner, and at least one jacket surrounding thereflective insulation system, the reflective insulation system furthercomprising: at least one low emissivity reflective surface; and at leastone spacer system positioned between the liner and the jacket, thespacer system creating a generally uniform air gap between an outersurface of the liner and the inner surface of the jacket to createadditional R value for the flexible insulated duct, wherein the spacersystem further comprises a plurality of spaced-apart staves, eachspaced-apart stave extending from the outer surface of the liner tocreate the generally uniform air gap between the outer surface of theliner and the inner surface of the at least one jacket.
 10. The flexibleinsulated duct of claim 9, wherein each of the spaced apart staves areattached at one end thereof to the outer surface of liner such that whenthe liner is expanded, free ends of the spaced apart staves extend awayfrom the outer surface of the liner to create the generally uniform airgap and when the liner is compressed, ends of the spaced apart movetoward the outer surface of the liner.
 11. In a method of supplyingconditioned air to a space using a flexible insulated duct, theimprovement comprising using the duct of claim
 9. 12. The flexibleinsulated duct of claim 9, wherein the jacket further comprises eithertwo layers of polyester film that are adhered together, the two layersencapsulating a scrim blanket therebetween or a continuous tube ofpolyethylene material.
 13. The flexible insulated duct of claim 9,wherein the at least one low emissivity surface is on either an innersurface of the at least one jacket or the outer surface of the liner.14. The flexible insulated duct of claim 9, wherein at least one bulkinsulating layer is positioned between: an outer periphery of the atleast one spacer system and the inner surface of the jacket such thatthe generally uniform air gap is created between the outer surface ofthe liner and an inner surface of the at least one bulk insulatinglayer; or an outer periphery of the liner and an inner periphery of atleast one spacer system such that the generally uniform air gap iscreated between an outer surface of the at least one bulk insulatinglayer and an inner surface of the at least one jacket.
 15. The flexibleinsulated duct of claim 14, further comprising a plurality of the atleast one spacer system and the at least one bulk insulating layersarranged to create a plurality of generally uniform air gaps.
 16. Theflexible insulated duct of claim 9, further comprising a plurality ofthe at least one spacer system and the at least one jacket arranged tocreate a plurality of generally uniform air gaps.
 17. An insulatedflexible duct comprising: a liner; a reflective insulation systemsurrounding the liner, and at least one jacket surrounding thereflective insulation system, the reflective insulation system furthercomprising: at least one low emissivity reflective surface; and at leastone spacer system positioned between the liner and the jacket, thespacer system creating a generally uniform air gap between an outersurface of the liner and the inner surface of the jacket to createadditional R value for the flexible insulated duct, wherein the spacersystem further comprises: a lattice cord and post blanket surroundingthe outer surface of the liner, tensioning of the lattice cord of thelattice cord and post blanket causing posts of the lattice cord and postblanket to orient in a generally perpendicular direction with respect tothe outer surface of the liner to create the generally uniform air gapbetween the outer surface of the liner and the inner surface of the atleast one jacket.
 18. In a method of supplying conditioned air to aspace using a flexible insulated duct, the improvement comprising usingthe duct of claim
 17. 19. The flexible insulated duct of claim 17,wherein the jacket further comprises either two layers of polyester filmthat are adhered together, the two layers encapsulating a scrim blankettherebetween or a continuous tube of polyethylene material.
 20. Theflexible insulated duct of claim 17, wherein the at least one lowemissivity surface is on either an inner surface of the at least onejacket or the outer surface of the liner.
 21. The flexible insulatedduct of claim 17, wherein at least one bulk insulating layer ispositioned between: an outer periphery of the at least one spacer systemand the inner surface of the jacket such that the generally uniform airgap is created between the outer surface of the liner and an innersurface of the at least one bulk insulating layer; or an outer peripheryof the liner and an inner periphery of at least one spacer system suchthat the generally uniform air gap is created between an outer surfaceof the at least one bulk insulating layer and an inner surface of the atleast one jacket.
 22. The flexible insulated duct of claim 21, furthercomprising a plurality of the at least one spacer system and the atleast one bulk insulating layers arranged to create a plurality ofgenerally uniform air gaps.
 23. The flexible insulated duct of claim 17,further comprising a plurality of the at least one spacer system and theat least one jacket arranged to create a plurality of generally uniformair gaps.
 24. An insulated flexible duct comprising: a liner; areflective insulation system surrounding the liner, and at least onejacket surrounding the reflective insulation system, the reflectiveinsulation system further comprising: at least one low emissivityreflective surface; and at least one spacer system positioned betweenthe liner and the jacket, the spacer system creating a generally uniformair gap between an outer surface of the liner and the inner surface ofthe jacket to create additional R value for the flexible insulated duct,wherein the liner comprises a pair of polymer films, one polymer filmforming an inner surface of the liner and the other polymer film formingthe outside surface of the liner and, optionally a helical memberdisposed between the polymer films.
 25. In a method of supplyingconditioned air to a space using a flexible insulated duct, theimprovement comprising using the duct of claim
 24. 26. The flexibleinsulated duct of claim 24, wherein the jacket further comprises eithertwo layers of polyester film that are adhered together, the two layersencapsulating a scrim blanket therebetween or a continuous tube ofpolyethylene material.
 27. The flexible insulated duct of claim 24,wherein the at least one low emissivity surface is on either an innersurface of the at least one jacket or the outer surface of the liner.28. The flexible insulated duct of claim 24, wherein at least one bulkinsulating layer is positioned between: an outer periphery of the atleast one spacer system and the inner surface of the jacket such thatthe generally uniform air gap is created between the outer surface ofthe liner and an inner surface of the at least one bulk insulatinglayer; or an outer periphery of the liner and an inner periphery of atleast one spacer system such that the generally uniform air gap iscreated between an outer surface of the at least one bulk insulatinglayer and an inner surface of the at least one jacket.
 29. The flexibleinsulated duct of claim 28, further comprising a plurality of the atleast one spacer system and the at least one bulk insulating layersarranged to create a plurality of generally uniform air gaps.
 30. Theflexible insulated duct of claim 24, further comprising a plurality ofthe at least one spacer system and the at least one jacket arranged tocreate a plurality of generally uniform air gaps.